Set allow_overlapping_ips to True by default

Bug 1152141

Change-Id: I36b3a91ac9c52ea8371df3adc7fcd0f55ad27a58
Allow mongod service to launch on Fedora

Fixes bug 1144907

Previously, the mongod service may fail to launch, if the eager
filesystem freespace check trips over an SELinux AVC or finds
a lack of freespace (depending on the up-to-datedness of the
selinux-policy-targeted package and the disk size/usage in the
hosting instance).

We work around these issues by ensuring the selinux-policy-targeted
package is up-to-date when ceilometer is enabled on Fedora, and
also setting the --smallfiles option.

Change-Id: I74f21662aedf9cc07b9a335d22b833a8a80dfce2
Merge "Set allow_overlapping_ips to True by default"
Merge "Allow mongod service to launch on Fedora"